"Bloatedness, mood swings and acne are telltale signs that it's that time of the month," says Cat Gray, "but when my PMS arrives, menstruation and ovulation do not follow." Polycystic Ovary Syndrome (PCOS) is the leading cause of female infertility, and with 10% of women estimated to have the disorder, it's the most common hormonal condition to affect women of a child-bearing age.

Gray was diagnosed with PCOS when she was 19 and, now 31, she says it makes her feel "less of a woman" due to the lack of a monthly cycle and the impending barriers to starting a family. "My mother was the most upset, worrying that she wouldn't get grandchildren. For me, it's the visible side effects that hurt the most." Along with higher chances of infertility, heart disease and diabetes, the common symptoms include obesity, acne and hirsutism. High levels of testosterone can cause all kinds of hair, skin and weight issues, and Gray says her teens and 20s were marred with "being fat, spotty and, worst of all, hairy".

Amy De Luca hasn't been swimming or sunbathing since she was 12: "Puberty and PCOS triggered hair growth all over my chest and back and, 10 years on, I don't look or feel any better." For the hirsute woman, dealing with body hair can feel like fighting a losing battle, regardless of the amount of razors and lasers in her arsenal. Hirsutism isn't simply a case of excessive female body hair – it can manifest itself as male-like hair growth with coarse, wiry hair on the chest, tummy, chin and upper lip. The hair can regrow rapidly enough to require a daily or twice daily shave, a practice that can be as distressing as it is time consuming. De Luca makes the bittersweet observation that it's the fear of judgement, rather than the condition itself, that drives the routine: "I would love to no longer feel the need for constant de-fuzzing, but I am terrified of what others will think of me so I shave anyway."

This summer, hundreds if not thousands of women will be breaking the cycle for the first time, by foregoing the razor in order to raise funds and awareness for PCOS. Armpits4August is a collective of hirsute, polycystic and body-hair-positive women who are tired of the pressure to pluck and preen to perfection, and are setting the challenge to simply stop one practice on one area, for one month. Like a ladies' version of Movember, but with a decidedly feminist twist, the charitable event presents an obvious but underestimated alternative to hair removal. In the words of a 70s Clapton classic: let it grow.

The campaign invites all women to take a month off from their usual grooming regime, to see how it feels to break the habit of a lifetime in the name of a vital women's health cause. In doing so, the Armpits4August experience raises a couple of curious questions. First, do you feel under pressure to conform to any hair-related beauty standards? Secondly, how does your underarm garden grow? Those who aren't joining the hairy marathon can still sponsor other participants, with all proceeds going to the PCOS charity Verity.

Some of Armpits4August group are already au naturel and are all too familiar with the reigning criticism from the pro-depilation camp that being hairy is inextricably linked with being unhygienic and unattractive. Yet, scientific research identifies a useful job for armpit hair, in pushing sweat and odour-causing bacteria away from the skin. "Bacteria prefer to reside on underarm skin" [rather than underarm hair], states Dr Ansari in a recent cosmetology publication, the Handbook of Cosmetic Science and Technology. First-time grower Laura Brown concurs: "Until I stopped shaving, I never realised that clammy skin next to clammy skin seems gross … Just thinking about it makes me uncomfortable."

Is the idea of refusing rather than forgetting to depilate really that hard to digest? "It makes sense that it would be," says Armpits4August participant Brown, "given that all around us we see images of women with completely smooth, silky legs." With the exception of the unkempt, unready celebs that are papped for body-shaming style commentary, the majority of stars' photos are edited beyond reality to remove spots, pores, wrinkles, cellulite, stretch marks and follicular fuzz.

So perhaps a more progressive approach to PCOS and hirsutism is to encourage self-worth and self-acceptance. Counselling, support networks and advocacy can all help to empower women to shoot that negative body-image into smithereens. "I'm medically classed as a hirsute woman," says Sarah, one of the women behind Armpits4August. "I used to absolutely hate my body hair because of bullying. I feel better about it since meeting other feminists." In Sarah's case, the turning point came when she could speak with other body-positive women and share the hairy solidarity.

Since her diagnosis at the turn of the century, Gray has learned to live with her polycystic ovaries: "It hasn't been easy," she says, "since there's no medical cure and I'm unable to get pregnant naturally." Gray states that living a healthier lifestyle does help to manage her cholesterol levels, and that totally cutting out wheat and dairy has slightly reduced her excess weight, body hair and acne. "Some things, like my fertility, cannot be changed. But seeing other women who expose their condition and are still totally gorgeous has convinced me that attitudes can and will change." Celebrating or at least acknowledging the more diverse forms of female beauty might go some way towards normalising these so called imperfections, and degendering the choice to remove or display them.

For years now, straight hair has been the female ideal. But curls are back, along with short crops, rattails, dip dyes... Elizabeth Day throws away the straighteners – and asks what our changing style says about us